Representative Ed Butcher's proposed the plant for the city, capable of processing up to 400 horses a week.
However, Hardin's council unanimously passed an ordinance amending the current zoning rules to prohibit the slaughter of more than 25 animals in a seven-day period.
Mayor Kimberly Hammond provided a statement to the Equine Welfare Alliance in which she said:
"I have no deluded thoughts or feelings about the need for proper disposal or care of unwanted horses.
"As Mayor of a small city, it is my responsibility to make information available to our public, especially when it concerns public safety, health, and how their tax dollars are being spent.
"The way our City Industrial Park is set up, a business is required to hook up to City Water and Sewer. A horse slaughter facility running at 200-400 kills a week would have brought our waste water treatment plant to a screaming halt.
"Our city would have been forced to construct a new waste-water treatment plant that would capacitate the slaughter facility, at the cost of our taxpayers. The city most likely would not have been able to get aid with funding a $6-8 million treatment plant.
"I, as mayor, had our city attorney draft an ordinance that prohibited slaughter houses within the city limits. Upon first reading, our city council did not like the verbiage that there would be NO slaughter facilities.
"They thought it was unfair to the small mom and pop operations that could be looking for a commercial plot. So we changed the language to only prohibit facilities that would kill more than 25 animals in a seven-day period.
"Our decision was based purely on the adverse impact that a facility of this size and nature would have had on our City Waste Water Treatment Plant."
Alliance representatives Vicki Tobin and John Holland said the mayor's concerns were well-placed.
"Horse slaughter plants are notorious for their waste problems," they said.
"Horses have almost twice as much blood per pound of body weight as cattle and it has proven very difficult to treat."
The alliance said it applauded Hardin for its proactive legislation to preserve the environment of their city.